from math import sqrt
import sys
input = sys.stdin.readline

n = int(input())
P = list(map(float, input().split()))
Q = [list(map(float, input().split())) for _ in range(n)]

ans = 0.0
for i in range(n):
    for j in range(i + 1, n):
        for k in range(j + 1, n):
            a = [Q[i][l] - P[l] for l in range(3)]
            b = [Q[j][l] - P[l] for l in range(3)]
            c = [Q[k][l] - P[l] for l in range(3)]
            volume = abs(b[0] * c[1] * a[2] + c[0] * a[1] * b[2] + a[0] * b[1] * c[2]
            - c[0] * b[1] * a[2] - a[0] * c[1] * b[2] - b[0] * a[1] * c[2]) / 6
            u = [Q[j][l] - Q[i][l] for l in range(3)]
            v = [Q[k][l] - Q[i][l] for l in range(3)]
            area = sqrt((u[1] * v[2] - u[2] * v[1])**2
            + (u[2] * v[0] - u[0] * v[2])**2
            + (u[0] * v[1] - u[1] * v[0])**2) / 2
            ans += 3 * volume / area
print(ans)